Rid, Lew, and Alec really drive the point home.
Most guitarists are spoiled to ultra low prices on everything due to availabilty and imports. However if we played (as Rid said) a Piano, Organ, or other stringed instrument we would be thrilled to get a decent (insert part here) for 120 bucks. To simply have a slant piano tuned is around 70 bucks! And if you have an actual internal problem with a piano not only do you have to buy the parts, but you have to pay someone to COME OUT and fix it.
Dumping 200 bucks in a 500 dollar guitar is a really big deal, you're investing another 40% of what you paid into the guitar. Whereas if you spend 120 bucks getting the perfect pickup for a 2000 dollar guitar it isn't a big proportionally. I'm the world's worst I've been avoiding and magnet swapping and doing everything possible to avoid getting a new bridge pup for my PRS, but I'm going to have to probably get a CS pup for it because nothing else in the regular line is what I'm looking for, it's either too hot, not hot enough, or has the wrong EQ.